1. Field of the Invention
This invention relates generally to drainage receptacles and more particularly to an adjustable highly reliable drain receptacle for use in roof drainage systems.
2. Description of the Prior Art
As is well known in the art, successful roof drain installations are directly attributable to various factors which require careful consideration. Among such factors is the roof drain receptacle itself, which should be a highly reliable structure that is ideally capable of being adjusted or otherwise adapted to suit various roofing conditions, such as deck type, thickness, and the like, and does not require that an installer have a high degree of installation expertise.
Most prior art roof drain receptacles include a drain body having an annular flange which extends laterally from the upper end thereof and is in bearing engagement with the upper surface of the roof deck and is usually clampingly attached to the roof deck by means of an underdeck clamp to insure that the roof drain receptacle is properly supported and positively secured. The drain body has an upwardly opening sump for receiving water from the surface of the roof and is provided with a drain outlet which is connected to the leader pipe of the drain system.
When the roofing materials, which are supported on the roof deck, such as insulation, are less than a maximum thickness, usually about two inches, or the materials are tapered toward the drain to provide such a thickness proximate the drain, a flashing ring is attached to the upper end of the drain body and coacts therewith to sealingly attach the drain receptacle to a suitable flashing element or roofing membrane. A dome structure having a slot or other openings formed therein is carried atop the flashing ring to allow the free inflow of water and yet restrict the passage of solid materials, such as leaves, which could cause drain system blockage. This basic type of roof drain receptacle is highly reliable and simple to install. However, its use is limited to roof structures having a relatively small thickness of roofing materials proximate the roof drain receptacle as mentioned above.
Whenever the roofing materials proximate the roof drain receptacle installation location exceeds the predetermined maximum, some form of extension element must be used to raise the top of the roof drain receptacle up to the level of the top surface of the roof.
In some prior art structures, a fixed height extension collar is interposed between the upper end of the drain body and the flashing ring. In such cases, the upper end of the extension collar cooperates with the flashing ring for sealingly attaching the drain receptacle to the flashing element or roof membrane and the lower end of the extension collar is sealed by means of a suitable sealant or gasket to the upper end of the drain body. The use of such a fixed height extension collar provides no means for installation adjustments which means that the roof drain receptacle simply cannot be used unless the proper fixed height extension collar is ordered and supplied with the balance of the roof drain receptacle components. In addition to this, whenever the use of a sealant or gasket is required in the roof drain receptacle itself, installation time is increased, the integrity of the drain receptacle is dependent on the skills of the installer and the materials used in forming the seal, and seal failures can occur due to vibrations, expansion and contraction, and the like, as well as seal deterioration resulting from environmental effects.
In other prior art structures, the problems associated with the hereinbefore described fixed height extension collars are overcome, or at least reduced, by providing an adjustable extension collar which is externally threaded for adjustable threaded attachment to internal threads provided in the drain body per se, or by a special support ring mounted thereon. In a variation of the adjustable extension collar, threaded rods are employed to interconnect and vary the height of the adjustable extension collar relative to the drain body. In any case, the requirement for forming an internal seal between the adjustable extension collar and the drain body, is as much of a problem as it is in the fixed height extension structures described above.
Therefore, a need exists for a new and improved adjustably extensible roof drain receptacle which overcomes some of the problems and shortcomings of the prior art.